An image sensor is a semiconductor-based sensor receiving light and generating an electrical signal, and may include a pixel array having a plurality of pixels and a circuit for driving the pixel array. Such an image sensor has been widely applied to a smartphone, a tablet PC, a laptop computer, a television, and the like, in addition to a camera for capturing still or moving images. Recently, research into various package technologies for effectively mounting an image sensor on a device such as a smartphone, a tablet PC, a laptop computer, or the like, as well as in a camera, has been actively conducted.